UPDATE: When I push up on the rear of the front drive shaft where it enters the transfer case, there's a bit of play - probably about 1/8". Seems to me that might indicate the front bearing in the transfer case is bad.
I called my dealership for a quote on replacing the bearing, and the service rep told me it would make more sense to replace the entire transfer case, as Parts & Labor on both jobs were withing $200 of each other, and the case replacement would come with a 3 yr/36,000 mile warranty - whereas the bearing replacement alone would only come with a one year/12000 mile warranty. The price for the transfer case replacement, by the way, was $2300.00. Man, these are expensive toys.